1. Field of the Invention
The present invention relates to a developer cartridge integrally provided with a toner hopper containing toner and a development tank to which the toner in the toner hopper can be supplied according to toner density in the tank. In particular, the invention relates to a sealing means of a toner supply port used for supplying the toner from the toner hopper to the development tank, at a time when shipping the developer cartridge.
2. Description of the Prior Art
In an image-forming machine for performing an image formation by using toner, the image-forming machine is shipped with a development apparatus containing developer. In recent years, a typical development apparatus (developer cartridge) has been integrally provided with a toner hopper and a development tank used for processing. Further, the development tank contains two-component developer made of the toner and carrier, and the toner hopper includes the toner. The toner hopper is mounted above the development tank, and a toner supply port is provided between the toner hopper and the development tank. A toner supply roller having a surface made of an elastic material such as sponge is mounted on the side of the toner hopper with respect to the toner supply port. The toner supply roller is operated to rotate so that the toner in the toner hopper can be supplied through the toner supply port to drop in the development tank. When shipping the developer cartridge, the development tank and the toner hopper contain the developer and the toner as described hereinbefore, respectively. In addition, toner density in the development tank is adjusted to a predetermined density.
However, if shipping the developer cartridge in the condition as set forth above, the toner hopper may spill the toner into the development tank due to, for example, vibrations. As a result, the toner density in the development becomes high. Further, the toner supply roller has the surface formed of the elastic material such as sponge, and has a lower surface side contacting the toner supply port with pressure. Accordingly, the lower surface side of the toner supply roller may be deformed along an opening of the toner supply port if stored in the above condition for a long period. As a result, there is a problem of causing excessive high starting torque of the toner supply roller.
In order to avoid these problems, some of the conventional developer cartridges are shipped without containing the developer (the toner and the carrier). However, the developer should be supplied by a service man or a user himself when installing the development apparatus. As a result, there is another drawback that a complicated operation is required for supplying the toner during the installation operation.